Crucial 4GB Single DDR3 1600 MT/s PC3-12800 CL11 Unbuffered UDIMM 240-Pin Desktop Memory Module CT51264BA160B at Amazon.com
OWC 16GB (2x8GB) ram Upgrade PC3-12800 DDR3L 1600MHz sodimm 204 Pin CL11 Memory Upgrade Kit Compatible with Late iMac, Mac Mini, and MacBook Pro Computer at Amazon.com
4GB DDR3-1600MHz PC3-12800 240-pin 1.5V 1Rx8 Non-ECC Unbuffered Desktop Memory by NEMIX RAM at Amazon.com
8GB (2 X 4GB) DDR3 1600MHz PC3-12800 240-pin Memory RAM DIMM Kit for Desktop PC by NEMIX RAM